Electrical resistors



May 24, 1966 c. HOY ETAL- 3,253,244

ELECTRICAL RES ISTORS Filed Nov. 6, 1965 F1604 FIG, 5

22 55 35 `|3Z\ @1344 4f1/ ,34% 35 38 WW /37/36 5gg 214 @14 (53 L56 INVENTORS .Leland C'. Ho b BY Wl'llzhm N..5`c ink United States Patent O 3,253,244 ELECTRICAL RESISTORS Leland C. Hoy, Skokie, and William N. Schink, Crystal Lake, Ill., assignors to Indak Manufacturing Corp., Northbrook, Ill., a corporation of Illinois Filed Nov. 6, 1963, Ser. No. 321,760 6 Claims. (Cl. 338-319) This invention relates to electrical resistors which will have many uses, but are especially applicable to certain types of service in automobiles and other vehicles.

A general object of the present invention is to provide new and improved electrical resistors of the type comprising one or more coils of resistance wire which are supported entirely by the wire leads at the ends of the coils.

A further object is to provide new and improved resistors of the foregoing character in which the resistance coils are in the open and exposed for free circulation of air around the coils to afford adequate cooling of the` coils, but in which new and improved guards are provided to prevent the coils from being damaged by handling and shipment.

It is a further object to provide new and improved resistors'of vthe foregoing character in which the guards are so arranged as to prevent the resistance coils from being crushed, bent or otherwise damaged when the resistors are shipped or handled in large numbers in bulk. In this way,.a large number of resistors may be shipped or handled in a single container without the necessity of going to the expense of providing small or individual shipping containers.

Another .object is to provide resistors having new and improved -guard means of the foregoing character vwhich may be provided at very little additional cost.

Further objects and advantages of the present invention will appear from the following description, taken with the accompanying drawings in which:

FIGS. 1 and 2 are front and side elevational views of a resistor to be described as an illustrative embodiment of the present invention.

FIG. 3 is a sectional View taken generally along the line 3 3 in FIG. 1.

FIGS. 4 and 5 are top and bottom views of the resistor of FIG. l.

FIGS. 6 and 7 are front and side views of a modied resistor.

FIG. 8 is a sectional view taken generally along the line 8 8 in FIG. 6.

vFIGS. 9 and l0 are top and bottom views of the resistor of FIG. 6.

FIG. 11 is a sectional view similar to a portion of FIG. 3 but drawn to a larger scale to show details Of the construction.

It will be seen that FIG. 1 illustrates a resistor 20 which may comprise one or more resistance elements. The illustrated resistor 20 has two resistance elements 22 and 24 which are in the form of open coils of resistance wire; The ends of the resistance coils 22 and 24 are formedv into tangentially extending leads 26, 27, 28 and 29. The leads 26-29 provide the entire support for the coils 22 and 24, which otherwise are open and unsupported.

It will be seen that the leads 26-29 are secured to metal lugs or terminal bars 32, 33 and 34 which are mounted on an insulating plate or other supporting member 35. The lower ends of the terminal bars 32-34 may be formed into prongs or blades 36, 37 and 38 which extend through slots or openings 40, 41 and 42 in the insulating support 35. The prongs 36-38 may be staked or otherwise suitably secured to the insulating plate 35, as shown in detail in FIG. l1.

In this case, the resistance coil 22 is connected between the terminal bars 32 and 33. The other resistance coil 24 is conunected between the terminal bars 33 and 34. The leads 26-29 are suitably secured to the terminal bars 3234. In this case, each of the leads is inserted through two loops 44 which are struck or punched from each of the terminal bars 3244. The central terminal bar 33 is formed with four such loops to receive the end leads 27 and 28. After the wire leads have been inserted, the loops 44 are flattened or clenched so as to clamp the leads tightly to the terminal bars. It will be recognized that the leads could be welded or otherwise secured to the terminal bars.

The illustrated prongs 36, 37 and 38 are adapted to receive an electrical plug or other connector, whereby the resistance elements 22 and 24 may be connected into any desired electrical circuit. The illustrated resistor 20 is especially well adapted for use in the electrical circuit for the heater of an automobile, to control the speed of the blower for the heater. The electrical circuit is normally arranged so that either or both of the resistance elements 22 and 24 may be connected in series with the blower motor, to reduce the speed of the motor. The resistor Ztl may be mounted on the main housing or duct of the heater, so that the resistance coils 22 and 24 will be located within the duct, in the stream of air produced by the blower. The air stream flows through the coils 22 and 24 and is efective to vcool the coils. The heat transferred from the resistance coils 22 and 24 to the air stream is not Wasted because it is added to the heat delivered by the heater to the inside of the automobile. The connector prongs 36-33 may extend outside the housing or duct of the blower, so as to be accessible for engagement by the electrical connector of the blower circuit. In FIG. 1, the `wall of the heater duct is shown in broken lines at 46. An opening 48 may be formed in the wall 46 to receive the resistor 20. Screws 50 or other fasteners may be employed to secure the insulating plate 35 to the wall 46. It will be seen that holes 52 are formed in the plate 35 to receive the screws 50.

terminal bars 32, 33 and 34 are formed with guards 54,

55 and 56 which extend above and partially surroundr the resistance coils 22 and 24 so as to protect the resistance coils against being crushed, bent or otherwise damaged in the course of handling or shipment. Inasrnuch as the coils 22 and 24 are supported solely by their leads, the coils are fairly fragile and subject to such mechanical damage. As shown, each of the guards 54-56 is formed integrally With the corresponding terminal lug. Each of the guards 54-56 is in the form of a bar or plate which extends upwardly from the corresponding terminal lug to a point above the upper extremities .of the resistance coils 22 and 24. It will be seen that the guards 54 and 56 for the outside terminal lugs 3234 are offset outwardly from the corresponding lugs. Thus, the guards 54 and 56 have lower ange portions 58 and 59 which are bent outwardly from the lugs '32-34 and extend horizontally between the lugs and the guards. The guard 55 on the central lug 33 is in the same plane as the lug and constitutes an upward extension thereof. It will be seen that the guards 54 and 56 are parallel to each other, at op posite ends of the resistor. The central guard 55 is at right angles to the guards 54 and 56 and is located substantially midway therebetween. The resistance coils 22 and 24 are arranged end to end.

Guards 54, 55 and 56 are particularly effective in protecting the resistance coils 22 and 24 against damage when the resistors 20 are shipped or handled in bulk with a large number of resistors in a single container. Under these conditions, the resistors tend to damage one. anv other, but this tendency is eifectively controlled by the guards 54 and 56. Thus, the guards make it possible to ship the resistors in bulk while greatly reducing the incidence of resistors which are crushed or otherwise damaged. Shipment in bulk eliminates the cost of small or individual shipping containers.

It will be noted that the resistance elements 22 and 24 are partly enclosed on three sides by the guards 54-56. The outside guards 54 .and y56 correspond generally in Width to the diameter of the resistance element 24, which is slightly larger in diameter than the resistance element (Z2 FIGS. 6410 illustrate a modified resistor 125i which is |basically similar to the resistor of FIGS. 1-5. To avoid repetition of description, the various components of the resistor 120 have been given the same reference characters as in the case of the resistor 20, but with the addition of the prefix 1. Thus, only the differences between the resistors 120 and 20 need be specifically described.

`It will be seen that the resistance elements 122 and 124 are positioned side by side, rather than end to end, as in the case of the resistance elements 22 and A24. The axes of the resistance coils 122 and l124 extend .generally perpendicular to the plane of the central terminal lug '133, rather than parallel thereto.

The outside terminal lugs 1132 and 134 and the corresponding guards 1154 and 155 correspond generally in width to the length of the resistance coils 122 and 124, and thus are considerably wider than the lugs 32 and 34 and the guards 54 and 56 of FIGS. 1-5. The insulating plate 1:35 is also Wider than the plate 35.

The guards 154, 155 and 1156 partially surround the l resistance coils 122 and 124 on three side thereof, as in the case of the frst embodiment. The guards 154-156 pnoject above the upper extremities of the resistance coils 11.22 and 124 and -aord mechanical protection for the coils, so as to prevent the coils from being crushed or otherwise damaged in the course of handling or shipment.

The guards 1544156 may be formed with a plurality of perforations or holes 164 which provide improved circulation of air around the resistance coils 122 `and |124, so that the coils will lbe `cooled more effectively.4 `In most cases, however, these perforations 164 may be omitted. The perforations `164 may also be formed in the terminal lugs 132, 133 and 134. The terminal lugs 32-34 and the guards -5'4-56 of FIG. 1 may also be formed with such perforations, if desired.

lIt twill tbe recognized that the resistors of the present invention `are inexpensive yet are sturdy in construction. The guards, formed integrally with the terminal lugs, protect the resistance coils from being crushed, bent or otherwise damaged, particularly when the resistors are handled or shipped in bulk.

Various other modifications, alternative constructions and equivalents maybe employed without departing from the true spirit and scope of the present invention, as exemplified in the foregoing description and deiined in the following claims.

We claim:

1. An electrical resistor,

comprising the combination of a flat insulating board,

at least two terminal lugs mounted on said insulating .board and projecting from one side thereof generally perpendicular thereto,

at least one coil of resistance wire extending between said terminal lugs and having end leads connected to said lugs adjacent said insulating board,

said lea-ds constituting the sole means of support for said coil,

said coil being disposed .with its axis generally parallel to said insulating board,

and guard Imembers formed integrally with said terminal lugs and projecting therefrom away from said insulating .board and generally perpendicular thereto, said guard members projecting from said terminal lugs beyond the outline of said coil to afford mechanical protection for said coil during shipment and handling.

2. An electrical resistor,

comprising the combination of a iiat insulating board,

at yleast two terminal lugs mounted on said insulating board :and projecting from one side thereof gen- Y erally perpendicular thereto,

at least one coil of resistance wire extending between said terminal lugs and having end leads connected to said lugs adjacent said insulating board,

said leads constituting the sole means of support for said coil,

said coil ybeing disposed with its axis generally parallel to said insulating board,

and guard members formed integrally with said terminal lugs and projecting therefrom away yfrom said insulating board and generally perpendicular thereto,

said guard members projecting from said terminal lugs 'beyond the outline of said coil to afford mechanical protection for said coil dur-ing shipment and handling,

said guard members being formed with perforations to provide for free air circulation around said coil.

3. An electrical resistor,

comprising the combination of a fiat insulating board,

at least two terminal lugs mounted on said insulating board and projecting from one side thereof generally lperpendicular thereto,

at least one coil of resistance wire extending between said terminal lugs and having end leads connected to said lugs adjacent said insulating board,

said leads constituting the sole means of support for said coil,

said coil being disposed with its axis generally parallel to said insulating board,

and guard members formed integrally with said terminal lugs `and projecting therefrom away from said insulating board and generally perpendicular thereto,

said guard members projecting from said terminal lugs beyond the outline of said coil to afford mechanical protection for said coil during shipment and handling,

said guard members being formed with perforations to provide for free air circulation around said coil,

at least one of said guard members being offset from the corresponding terminal lug and away from said coil .to provide spacing between said offset guard member and said coil.

4. An electrical resistor,

comprising the combination of a flat insulating board,

at least rst, second and third terminal lugs mounted on said insulating board and projecting from one side thereof and generally perpendicularl thereto,

said terminal lugs being in the form of sheet metal strips,

a `first coil of resistance wire .connected between said iirst and second terminal lugs 'and having end leads secured there to adjacent said insulating board,

said first coil having its axis generally parallel to said insulating board,

a second coil of wire connected between said second and third terminal lugs and having end leads secured thereto adjacent said insulating board,

said second coil having its axis generally parallel to said insulating board,

said coils having open convolutions with air spaces therebetween,

said ends leads constituting the sole means of support for said coils,

and first, second and third guard members formed integrally with said terminal lugs and projecting therefrom away from said insulating board and generally perpendicular thereto,

said guard members projecting from said terminal lugs and past the outlines of said coils,

said guard members being disposed around said coils on three sides thereof and `affording mechanical protection for said coils -against damage during shipment and handling. f

5. An electrical resistor,

comprising the combination of a fiat insulating board,

at least iirst, second and third terminal lugs mounted on said insulating board and projecting from one side thereof and generally perpendicular thereto,

said terminal lugs being in the form of sheet metal strips,

a first coil vof resistance wire connected between said first and second terminal lugs and having end leads secured thereto adjacent said insulating board,

said rst coil having its axis generally parallel to said insulating board,

a second coil of wire connected between said second and third terminal lugs and having end leads secured thereto adjacent said insulating board,

said second coil having its aXis generally parallel to said insulating board,

said coils having open convolutions with air spaces therebetween,

said end leads constituting the sole means of support for said coils,

and first, second and third guard members formed integrally with said terminal lugs and projecting therefrom away from said insulating 4board and generally perpendicular thereto,

said guard members projecting from said terminal lugs and past the outlines of said coils,

said guard members .being disposed around said coils 0n three sides thereof and afording mechanical protection for said coilsagainst damage during shipment and handling,

saidguard members being formed with perforations to provide for free air circulation around said coils.

6. An electrical resistor,

comprising the combination of a flat insulating board,

at least first, second and third terminal lugs mounted on said insulating board and projecting from one side thereof and generally perpendicular thereto,

said terminal lugs being in the form of sheet metal strips,

a first coil of resistance wire connected between said rst 'and second terminal lugs and having end leads secured thereto adjacent said insulating board,

said first coil having its aXis generally parallel to said insulating board,

a second coil of Wire connected between said second and third terminal lugs and having end leads secured thereto adjacent said insulating board,

said second coil having its axis generally parallel to said insulating board,

said coils having open convolutions with air spaces therebetween,

said end leads constituting the sole means of support for said coils,

land first, second and third guard members formed integrally with said terminal lugs and projecting therefrom away Afrom said insulating board and generally perpendicular thereto,

said guard members projecting from said terminal lugs and past the outlines of said coils,

said guard members being disposed 'around said coils -on three sides thereof 4and affording mechanical protection for said coils against damage during shipment and handling,

said guard members being formed with perforations to provide for free, air circulation around said coils,

at least one of said guard members being offset laterally from the corresponding terminal lug and away from said coils to afford spacing between said offset guard Imember and said coils.

References Cited by the Examiner UNITED STATES PATENTS 1,788,354 1/1931 Alden 399-277 X 2,384,797 9/ 1945 Cerny et al. 219-270 2,768,677 10/1956 Traver 158-115 2,850,084 9/1958 Kunzler 317-87 X 2,865,012 12/1958 Black 339-228 2,912,623 11/1959 Tuttle 317-87 2,958,063 10/1960 Stawnyck 339-112 X 3,139,558 6/1964 Lindberg 317-98 FOREIGN PATENTS 18,744 3/ 1930 Australia.

[of 1929 626,247 5 1927 France.

RICHARD M. WOOD, Primary' Examiner.

V. Y. MAYEWSKY, Assistant Examiner. 

1. AN ELECTRICAL RESISTOR, COMPRISING THE COMBINATION OF A FLAT INSULATING BOARD, AT LEAST TWO TERMINAL LUGS MOUNTED ON SAID INSULATING BOARD AND PROJECTING FROM ONE SIDE THEREOF GENERALLY PERPENDICULAR THERETO, AT LEAST ONE COIL OF RESISTANCE WIRE EXTENDING BETWEEN SAID TERMINAL LUGS AND HAVING END LEADS CONNECTED TO SAID LUGS ADJACENT SAID INSULATING BOARD, SAID LEADS CONSTITUTING THE SOLE MEANS OF SUPPORT FOR SAID COILS, SAID COIL BEING DISPOSED WITH ITS AXIS GENERALLY PARALLEL TO SAID INSULATING BOARD, AND GUARD MEMBERS FORMED INTEGRALLY WITH SAID TERMINAL LUGS AND PROJECTING THEREFROM AWAY FROM SAID INSULATING BOARD AND GENERALLY PERPENDICULAR THERETO, SAID GAURD MEMBERS PROJECTING FROM SAID TERMINAL LUGS BEYOND THE OUTLINE OF SAID COIL TO AFFORD MECHANICAL PROJECTION FOR SAID COIL DURING SHIPMENT AND HANDLING. 